Preheat the oven to 375°F.

In a mixing bowl, combine the chopped spinach, feta cheese, sun-dried tomatoes (if using), minced garlic, oregano, salt, and pepper. Mix well until all ingredients are evenly combined.

Place the chicken breasts on a cutting board and carefully slice each breast horizontally, creating a pocket without cutting all the way through.

Stuff each chicken breast with the spinach and feta mixture, then roll them up tightly. Secure each roll with toothpicks or tie with kitchen twine.

In a large oven-safe skillet, heat the olive oil over medium heat. Add the chicken rolls and sear for about 3-4 minutes on each side until golden brown.

Pour the chicken broth and lemon juice into the skillet around the chicken. Bring to a simmer, then transfer the skillet to the preheated oven.

Bake for 20-25 minutes or until the chicken is cooked through and reaches an internal temperature of 165°F.

Remove from the oven and let the chicken rest for 5 minutes before removing the toothpicks or twine. Slice and serve warm.